Need to escape non-ASCII characters in JavaScript

Question

Is there any function to do the following?

var specialStr = 'ipsum áá éé lore';
var encodedStr = someFunction(specialStr);
// then encodedStr should be like 'ipsum \u00E1\u00E1 \u00E9\u00E9 lore'

I need to encode the characters that are out of ASCII range, and need to do it with that encoding. I don't know its name. Is it Unicode maybe?

@mplungjan this has nothing to do with URI encoding; neither of the linked questions do what the OP wants. — Domenic
– Domenic, Commented Sep 21, 2011 at 12:16
See javascripter.net/faq/escape.htm or, even better, see developer.mozilla.org/en/Core_JavaScript_1.5_Guide/…. — Cloudy
– Cloudy, Commented Sep 21, 2011 at 12:17
@mplungjan you yet again seem to have failed to read the OP's question. — Domenic
– Domenic, Commented Sep 21, 2011 at 12:20
@Domenic - granted, I deleted the first links but the last link is more relevant (not the accepted answer but some of the other answers), I object to "Yet again" — mplungjan
– mplungjan, Commented Sep 21, 2011 at 12:21

Domenic · Accepted Answer · 2011-09-21 12:24:50Z

20

This should do the trick:

function padWithLeadingZeros(string) {
    return new Array(5 - string.length).join("0") + string;
}

function unicodeCharEscape(charCode) {
    return "\\u" + padWithLeadingZeros(charCode.toString(16));
}

function unicodeEscape(string) {
    return string.split("")
                 .map(function (char) {
                     var charCode = char.charCodeAt(0);
                     return charCode > 127 ? unicodeCharEscape(charCode) : char;
                 })
                 .join("");
}

For example:

var specialStr = 'ipsum áá éé lore';
var encodedStr = unicodeEscape(specialStr);

assert.equal("ipsum \\u00e1\\u00e1 \\u00e9\\u00e9 lore", encodedStr);

edited Sep 21, 2011 at 12:24

answered Sep 21, 2011 at 12:12

Domenic

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2 Comments

Hanoi Over a year ago

Thanks a lot Domenic, i will use this solution ;)

ToniG Over a year ago

To decode, just assign the value to a variable: let a = "\u00e1"; console.log(a); // prints á

Max Murphy · Accepted Answer · 2018-02-23 19:09:19Z

3

If you need hex encoding rather than unicode then you can simplify @Domenic's answer to:

"aäßåfu".replace(/./g, function(c){return c.charCodeAt(0)<128?c:"\\x"+c.charCodeAt(0).toString(16)})

returns: "a\xe4\xdf\xe5fu"

answered Feb 23, 2018 at 19:09

Max Murphy

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1 Comment

some Over a year ago

Do you know that the charcode can be larger than 255? "ė".replace(/./g, function(c){return c.charCodeAt(0)<128?c:"\\x"+c.charCodeAt(0).toString(16)}) returns \x117 and that will lead to trouble.

fmsf · Accepted Answer · 2011-09-21 12:16:01Z

1

Just for information you can do as Domenic said or use the escape function but that will generate unicode with a different format (more browser friendly):

>>> escape("áéíóú");
"%E1%E9%ED%F3%FA"

answered Sep 21, 2011 at 12:16

fmsf

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2 Comments

Domenic Over a year ago

Interestingly enough: escape("☃") === "%u2603" while escape("á") === "%E1". I wonder how they decide when to switch formats and add a "u" at the beginning...

Domenic Over a year ago

Ah, well, MDN says "The escape and unescape functions do not work properly for non-ASCII characters and have been deprecated.": developer.mozilla.org/en/Core_JavaScript_1.5_Guide/… so maybe that's the source of the inconsistency.

Jens · Accepted Answer · 2019-03-28 16:07:11Z

1

This works for me. Specifically when using the Dropbox REST API:

   encodeNonAsciiCharacters(value: string) {
        let out = ""
        for (let i = 0; i < value.length; i++) {
            const ch = value.charAt(i);
            let chn = ch.charCodeAt(0);
            if (chn <= 127) out += ch;
            else {
                let hex = chn.toString(16);
                if (hex.length < 4)
                    hex = "000".substring(hex.length - 1) + hex;
                out += "\\u" + hex;
            }
        }
        return out;
    }

answered Mar 28, 2019 at 16:07

Jens

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